Making a venturi

I have an Excalibur skimmer that used to have a Rio hyper flow on it and burnt out.
What I am trying to do is hook up my 802 and create the venturi. I have tried all different methods of adding the tube but still cant get it to suck in air. I have a 3/8" hole about 1/2" up the stem of the pump with the wider type tube that came with the skimmer.
Anyone know what im doing wrong?

 

Im not sure I completely understand your set up, but on my skimmer the air hose is connected to the input side of the pump, not the output side. Maybe try that??

 

Yup, connect it to the Input side. This creates suction, drawing in the air. The size of hole dictates how much air is drawn in. If you make the hole to big, you may need to put a restrictor on it, to tune it per se.

 

Ok. Thanks guys.
Ill give it a try.

 

Just curious. I threw my old rio out, but how did that one take in air?
Isn't a true venturi pulled in through the flow of the water? For some reason I thought thats how the rio worked, but cant remember.

 

A venturi works by water moving through a nozzle creating a low pressure area. It can be made on the suction or discharge of a pump. Most needle wheel skimmers use a venturi on the suction and use a needle wheel to chop up the air.

A venturi on the discharge needs a high pressure pump to push water across a venturi that sucks air in and mixes it through brute force.

Do you have a needle wheel impeller?

 

I dont think so. Its just a Hagen 802.
But I dont think the original Rio had a needle wheel either.